The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global ...scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.
•Mixtures of oak and pine show clear but limited overyielding under Dutch conditions.•Overyielding productivity is mostly attributed to oak, in all climatic scenarios.•Oak productivity decreases and ...pine productivity increases under climate change.•Scots pine has a clear competitive advantage over oak on resource-limited soils.•Direction of competition may shift in favor of Scots pine in a changing climate.
Mixed-species forests have become widely studied in the recent years because of their potential to mitigate risks associated with climate change. However, their growth dynamics are often difficult to predict because species interactions vary with climatic and edaphic conditions, stand structure and forest management. We examined species interactions in mixtures of Scots pine (Pinus sylvestris) and pedunculate oak (Quercus robur) under climate change and for varying soil conditions in the Netherlands, over a period of 30 years. We parameterized, calibrated and validated the 3-PGmix model for mixing effects in Scots pine and oak mixtures and analysed these effects under climate change. 3-PGmix performed well for the variety of forest stands examined throughout the Netherlands. Furthermore, it was also able to reproduce mixing effects for each species in mixtures compared to monocultures for the growing conditions examined. Simulated climate change resulted in lower productivity of oak and higher productivity of Scots pine, compared to the current climate. This was observed for both monospecific stands and mixtures. The mixture of Scots pine and oak showed clear but limited overyielding (mixture yield greater than the mean of the monocultures), which was mainly attributed to oak. This was maintained under the most extreme climate scenario for 2050, implying that for oak, increased growth due to mixing with Scots pine was larger than the reduction in productivity under the future climate. On resource-limited soils, Scots pine competitiveness was increased, and this was maintained under a warmer and drier climate. Our results suggest that projected changes in climate will influence species interactions and result in increased Scots pine productivity, notably on poor sandy soils, which are typical of the Netherlands.
Climate-Smart Forestry: the missing link Verkerk, P.J.; Costanza, R.; Hetemäki, L. ...
Forest policy and economics,
June 2020, 2020-06-00, 20200601, Volume:
115
Journal Article
Peer reviewed
Open access
To achieve the objectives of the Paris Climate Agreement, a significant reduction in carbon dioxide emissions is needed, as well as increased removals by carbon sinks. In this context, we argue that ...Climate-Smart Forestry is a necessary, but still missing component in national strategies for implementing actions under the Paris Agreement. Climate-Smart Forestry is needed to (a) increase the total forest area and avoid deforestation, (b) connect mitigation with adaption measures to enhance the resilience of global forest resources, and (c) use wood for products that store carbon and substitute emission-intensive fossil and non-renewable products and materials. Successful Climate-Smart Forestry has important policy implications on finding the right balance between short and long-term goals, as well as between the need for wood production, the protection of biodiversity and the provision of other important ecosystem services. CSF thus can provide important co-benefits that are increasingly being recognized as essential for sustainable well-being.
•Climate-Smart Forestry (CSF) is missing in global decarbonization strategies.•CSF should increase effectiveness of carbon removals and enhance forest resilience.•Policy needs to balance wood production, biodiversity protection and ecosystem services.•Policy must find the right balance between short and long-term goals.
We present a new synthesis, based on a suite of complementary approaches, of the primary production and carbon sink in forests of the 25 member states of the European Union (EU-25) during 1990-2005. ...Upscaled terrestrial observations and model-based approaches agree within 25% on the mean net primary production (NPP) of forests, i.e. 520±75 g C m⁻² yr⁻¹ over a forest area of 1.32 x 10⁶ km² to 1.55 x 10⁶ km² (EU-25). New estimates of the mean long-term carbon forest sink (net biome production, NBP) of EU-25 forests amounts 75±20 g C m⁻² yr⁻¹. The ratio of NBP to NPP is 0.15±0.05. Estimates of the fate of the carbon inputs via NPP in wood harvests, forest fires, losses to lakes and rivers and heterotrophic respiration remain uncertain, which explains the considerable uncertainty of NBP. Inventory-based assessments and assumptions suggest that 29±15% of the NBP (i.e., 22 g C m⁻² yr⁻¹) is sequestered in the forest soil, but large uncertainty remains concerning the drivers and future of the soil organic carbon. The remaining 71±15% of the NBP (i.e., 53 g C m⁻² yr⁻¹) is realized as woody biomass increments. In the EU-25, the relatively large forest NBP is thought to be the result of a sustained difference between NPP, which increased during the past decades, and carbon losses primarily by harvest and heterotrophic respiration, which increased less over the same period.
In order to map the spatial distribution of twenty tree species groups over Europe at 1 km × 1 km resolution, the ICP-Forest Level-I plot data were extended with the National Forest Inventory (NFI) ...plot data of eighteen countries. The NFI grids have a much smaller spacing than the ICP grid. In areas with NFI plot data, the proportions of the land area covered by the tree species were mapped by compositional kriging. Outside these areas, these proportions were mapped with a multinomial multiple logistic regression model. A soil map, a biogeographical map and bioindicators derived from temperature and precipitation data were used as predictors. Both methods ensure that the predicted proportions are in the interval 0,1 and sum to 1. The regression predictions were iteratively scaled to the National Forest Inventory statistics and the Forest map of Europe. The predicted proportions for the twenty tree species were validated by the Bhattacharryya distance between predicted and observed proportions at 230 plot data separated from the calibration data. Besides, the map with the predicted dominant species was validated by computing the error matrix. The median Bhattacharryya distance in the subarea with NFI plot data was 1.712, whereas in the subarea with ICP-Level-I data, this was 2.131. The scaling did not significantly decrease the Bhattacharryya distance. The estimated overall accuracy of this map was 43%. In areas with NFI plot data, overall accuracy was 57%, outside these areas 33%. This gain was mainly attributable to the much denser plot data, less to the prediction method.
This paper, based on a literature review, presents a quantitative overview of the role of natural disturbances in European forests from 1850 to 2000. Such an overview provides a basis for modelling ...the possible impacts of climate change and enables one to assess trends in disturbance regimes in different countries and/or periods. Over the period 1950–2000, an annual average of 35 million m3 wood was damaged by disturbances; there was much variation between years. Storms were responsible for 53% of the total damage, fire for 16%, snow for 3% and other abiotic causes for 5%. Biotic factors caused 16% of the damage, and half of this was caused by bark beetles. For 7% of the damage, no cause was given or there was a combination of causes. The 35 million m3 of damage is about 8.1% of the total fellings in Europe and about 0.15% of the total volume of growing stock. Over the period 1961–2000, the average annual area of forest fires was 213 000 ha, which is 0.15% of the total forest area in Europe. Most types of damage seem to be increasing. This is partly an artefact of the improved availability of information. The most likely explanations for an increase in damage from disturbances are changes in forest management and resulting changes in the condition of the forest. Forest area, average volume of growing stock and average stand age have increased considerably, making the forest more vulnerable and increasing the resources that can be damaged. Since forest resources are expected to continue to increase, it is likely that damage from disturbances will also increase in future.
Forest Carbon Sinks in the Northern Hemisphere Goodale, Christine L.; Apps, Michael J.; Birdsey, Richard A. ...
Ecological applications,
June 2002, Volume:
12, Issue:
3
Journal Article
Peer reviewed
There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary ...greatly. National forest inventories provide strong, measurement-based constraints on the magnitude of net forest carbon uptake. We brought together forest sector C budgets for Canada, the United States, Europe, Russia, and China that were derived from forest inventory information, allometric relationships, and supplementary data sets and models. Together, these suggest that northern forests and woodlands provided a total sink for 0.6-0.7 Pg of C per year (1 Pg = 1015g) during the early 1990s, consisting of 0.21 Pg C/yr in living biomass, 0.08 Pg C/yr in forest products, 0.15 Pg C/yr in dead wood, and 0.13 Pg C/yr in the forest floor and soil organic matter. Estimates of changes in soil C pools have improved but remain the least certain terms of the budgets. Over 80% of the estimated sink occurred in one-third of the forest area, in temperate regions affected by fire suppression, agricultural abandonment, and plantation forestry. Growth in boreal regions was offset by fire and other disturbances that vary considerably from year to year. Comparison with atmospheric inversions suggests significant land C sinks may occur outside the forest sector.
Abstract Previously selected amyloid beta recognizing heavy chain antibody fragments (VHH) affinity binders derived from the Camelid heavy chain antibody repertoire were tested for their propensity ...to cross the blood–brain barrier (BBB) using an established in vitro BBB co-culture system. Of all tested VHH, ni3A showed highest transmigration efficiency which is, in part, facilitated by a three amino acid substitutions in its N-terminal domain. Additional studies indicated that the mechanism of transcellular passage of ni3A is by active transport. As VHH ni3A combines the ability to recognize amyloid beta and to cross the BBB, it has potential as a tool for non-invasive in vivo imaging and as efficient local drug targeting moiety in patients suffering from cerebral amyloidosis such as Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA).
We summed estimates of the carbon balance of forests, grasslands, arable lands and peatlands to obtain country-specific estimates of the terrestrial carbon balance during the 1990s. Forests and ...grasslands were a net sink for carbon, whereas croplands were carbon sources in all European countries. Hence, countries dominated by arable lands tended to be losing carbon from their terrestrial ecosystems, whereas forest-dominated countries tended to be sequestering carbon. In some countries, draining and extraction of peatlands caused substantial reductions in the net carbon balance. Net terrestrial carbon balances were typically an order of magnitude smaller than the fossil fuel-related carbon emissions. Exceptions to this overall picture were countries where population density and industrialization are small. It is, however, of utmost importance to acknowledge that the typically small net carbon balance represents the small difference between two large but opposing fluxes: uptake by forests and grasslands and losses from arable lands and peatlands. This suggests that relatively small changes in either or both of these large component fluxes could induce large effects on the net total, indicating that mitigation schemes should not be discarded a priori. In the absence of carbon-oriented land management, the current net carbon uptake is bound to decline soon. Protecting it will require actions at three levels; a) maintaining the current sink activity of forests, b) altered agricultural management practices to reduce the emissions from arable soils or turn into carbon sinks and c) protecting current large reservoirs (wetlands and old forests), since carbon is lost more rapidly than sequestered.
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